Structural and Architectural Evaluation of Bimetallic Nanoparticles: A Case Study of Pt−Ru Core−Shell and Alloy Nanoparticles

Journal Article · Thu Jan 01 04:00:00 EST 2009 · ACS Nano

DOI:https://doi.org/10.1021/nn900242v· OSTI ID:980488

Alayoglu, S; Zavalij, P; Eichhorn, B; Wang, Q; Frenkel, A; Chupas, P

A comprehensive structural/architectural evaluation of the PtRu (1:1) alloy and Ru at Pt core-shell nanoparticles (NPs) provides spatially resolved structural information on sub-5 nm NPs. A combination of extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), pair distribution function (PDF) analyses, Debye function simulations of X-ray diffraction (XRD), and field emission transmission electron microscopy/energy dispersive spectroscopy (FE-TEM/EDS) analyses provides complementary information used to construct a detailed picture of the core/shell and alloy nanostructures. The 4.4 nm PtRu (1:1) alloys are crystalline homogeneous random alloys with little twinning in a typical face-centered cubic (fcc) cell. The Pt atoms are predominantly metallic, whereas the Ru atoms are partially oxidized and are presumably located on the NP surface. The 4.0 nm Ru at Pt NPs have highly distorted hcp Ru cores that are primarily in the metallic state but show little order beyond 8 A. In contrast, the 1-2 monolayer thick Pt shells are relatively crystalline but are slightly distorted (compressed) relative to bulk fcc Pt. The homo- and heterometallic coordination numbers and bond lengths are equal to those predicted by the model cluster structure, showing that the Ru and Pt metals remain phase-separated in the core and shell components and that the interface between the core and shell is quite normal.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980488
• Report Number(s): BNL--93406-2010-JA
• Journal Information: ACS Nano, Journal Name: ACS Nano Journal Issue: 10 Vol. 3
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
99 GENERAL AND MISCELLANEOUS
ABSORPTION
ALLOYS
ATOMS
BOND LENGTHS
COORDINATION NUMBER
DISTRIBUTION FUNCTIONS
EVALUATION
FIELD EMISSION
FINE STRUCTURE
FUNCTIONS
INTERFACES
METALS
NANOSTRUCTURES
SHELLS
SPECTROSCOPY
TRANSMISSION
TWINNING
X-RAY DIFFRACTION
national synchrotron light source